For the villagers of Zewa, perched high in the snow-covered mountains of northern Iraq, it is not a question of when the tanks will arrive. They already have. Just down their slush-covered road, around 20 Turkish tanks were yesterday parked on the icy runway of a military base, ringed by barbed wire. A few Turkish soldiers could be seen scurrying around in the cold, attaching green tents to the tank's turrets.

Asked what they were doing, the reply was blunt. "We are not permitted to speak to you," one said. The villagers have grown used to the Turkish garrison on their doorstep- but resent its presence. "We are not happy about them being here," one Kurdish villager, Muhamed Muhamad, said.

"Whenever they go on exercises up in the mountains, they shoot our cattle. They've killed seven sheep. We'd like them to go home," he added.

The Turkish military has had a secretive presence inside northern Iraq for a long time. Its soldiers arrived here five years ago, their apparent mission to wipe out separatist Kurdish rebels from Turkey who were hiding up in the stony, treeless mountains.

The rebels have now all disappeared. But the Turkish military is still here, the villagers complain. Turkey's continuing negotiations to allow American troops to enter Turkey- so that the US military can open up its elusive northern front against Saddam Hussein- is not without its price.

As well as a generous package of financial assistance, Ankara is also insisting that thousands of its own troops should be allowed to enter the Kurdish self-rule enclave of northern Iraq. Turkey insists this would be a humanitarian operation. But the local Kurds are deeply suspicious, and recall the harsh treatment meted out to Turkey's own disaffected Kurdish population.

"I don't think the Turks are coming here out of altruism," one villager, 70-year-old Shahbaz Juma, dressed in traditional Kurdish baggy trousers and cummerbund, said. "In 1991 I was forced to flee to Turkey. I ended up in a refugee camp. It was horrible, like a prison. The Turks treated us terribly," he recalled.

The two Kurdish groups that control northern Iraq, the Kurdish Democratic Party (KDP) and the Patriotic Union of Kurdistan (PUK), want the American military to get rid of Saddam Hussein. But they fear Turkey's proposed 50km military "incursion" into their territory would, in reality, amount to little more than an old-fashioned invasion.

Its real, sinister purpose is to redraw the boundaries of modern Iraq, they believe. Turkey has always regarded the area as its backyard. For four centuries Iraq was ruled by Istanbul, and was a neglected and fading province of the vast Ottoman Empire.

British troops finally drove the Turks out of Baghdad in 1917. In the controversial settlement that followed, the League of Nations decided to incorporate the two northern cities of Mosul and Kirkuk into the new state of Iraq- a decision bitterly resented by Turkey.

Some 85 years later, historical tensions dating back to Britain's forgotten rule in the Middle East have resurfaced- and appear ready to ignite.

"If Turkish troops occupy our territory we will resist," Ihsan Qadir, a senior Kurdish official, and parliamentary advisor on Iraqi Kurdistan, said. "The Turks want to ensure the Kurds have no power." What did he mean by resist? "We will fight them," he said.

Increasingly, British and American strategists are having to contemplate a nightmare scenario: that having deposed Saddam Hussein in a successful military campaign, which may well start next week, Iraq slides rapidly into an ethnic and sectarian civil war, fanned by its neighbours Turkey, Saudi Arabia and Iran.

Downing Street and the White House will hardly have been encouraged by the news that Iranian-backed Iraqi opposition troops, under the command of a prominent exiled Iraqi Shia leader, Ayatollah Mohammad Baqir al-Hakim, had set up a new camp in northern Iraq.

The prospect of a full-scale conflict between Iraq's downtrodden Shia majority, and its ruling Sunni elite, which has traditionally supported Saddam Hussein and his Ba'ath party, is all too real, many Kurds feel.

Nowhere are the tensions more palpable than in the office of the Iraqi Turkoman Front, in the city of Irbil, yesterday protected by young, nervous Turkoman guards armed with gleaming Kalashnikovs.

The Turkomans are a small Turkish-speaking minority that have lived in Iraq since the 11th century- but who now find themselves cast in the role of fifth columnists. Two weeks ago Kurdish security officials arrested one of the front's leaders, Amir Ezad. They accused him of trying to sabotage last month's meeting of the Iraqi opposition in Irbil- and claimed he was an agent of the Mukhabarat, Iraq's notorious secret police.

The Turkomans deny any links with Baghdad, but admit they would welcome a Turkish invasion of northern Iraq. "We want Turkish troops to come so they can protect us," Nurettin Musullu, a front official, said. "When stability returns the Turkish and American troops should go back."

Iraq's unresolved ethnic divisions all appear to converge uneasily on the northern city of Kirkuk, currently controlled by Baghdad, and home to some of the country's largest oil deposits. The Turkomans insist that Kirkuk belongs to them - and say a 1947 census proves their case. The Kurds maintain that Kirkuk has always been Kurdish.

The reality is that after several decades of ruthless "Arabisation" by Saddam Hussein, which has seen both ethnic groups evicted from their homes and replaced by Arab settlers, Kirkuk is now predominantly Arab.

Turkey wants to send its troops into northern Iraq to prevent Kurdish militias from marching on the city and declaring a Kurdish homeland, locals believe. The Kurds say they are not interested in an independent state, and merely want a new federal Iraq. Either way few villagers in Zewa are prepared to give Ankara the benefit of the doubt.

"This is all about Turkey's self-interest," Fazel Muhamad, a 20-year-old Kurdish guerrilla said. "We have plenty of troops ourselves. If they come then we will fight them."